- "When" means something will definitely happen in the future.
- "If" is 条件的なこと. So it might happen, or it might not.
Please use English well!
The global average TOEFL speaking score is 19. The Japan average score is 15. My students' average top TOEFL speaking score is 23. Why? Because they don't use templates! If you have a clear voice and practice regularly, you should get 23 consistently too.